Here is a close-up of the two compressor wheels. The stock one is on the right and the Banks one is on the left. Note the difference in the pitch of the blades, and that every other blade on the Banks unit is a different height. These changes allow the wheel to move more air for a given rpm. They also make Jane whistle like a big rig under acceleration, which sounds really cool. A note on noise: Overall, I&#146;ve noticed very little change in the sound of the truck. Despite the much larger exhaust tubing and a flow-through muffler, the exhaust note seems no louder than stock, just a little more throaty. Other than the aforementioned whistle, the engine itself sounds no different.